Light fixtures are known which have a tube or a tubular housing, the ends are covered by end caps which are fitted thereon, and a light module is arranged inside the tube.
In this case it is known to use end caps which have a base and cylindrical collar extending from the base. The collar usually has the same external diameter as a central region of the tube. In order to enable assembly of the tube and the end cap, the ends of the tube have a region with reduced external diameter, so that the cylindrical part of the end cap can be pushed over this region. Between the end cap and the region with reduced diameter, a foamable cement is provided which foams during heating and thus connects the end cap and the tube end to one another. During foaming, in order to prevent the foaming cement from foaming out from the overlap region between the end cap and the region with a reduced external diameter of the tube, the end cap is fitted to a transition point from which the tube again has its normal, moderate diameter which, together with the end of the end cap, by reciprocal abutment, provides a seal against any escape of foaming cement. In other words, the end cap is pressed by its end onto the glass of the tube. As a result, an escape of foaming cement between the end of the end cap and the tube to the outside can be substantially prevented.
Furthermore, it is known for a driver device for driving the light module to be arranged on the end cap, wherein the driver device is inserted at least partially into the tube during assembly. The dimensions of the driver device are limited because of the region of the tube with a reduced external diameter. In other words, the reduction of the diameter of the tube limits the maximum possible radial overall size of the driver device.